The present invention is directed to a bipolar RF generator for an electrosurgical cutter/coagulator system and, more particularly, to a bipolar RF generator for producing a cutting waveform or a coagulating waveform having an aperiodic sequence of damped RF bursts.
Most electrosurgical systems which are employed to cut or coagulate tissue are based on the theory of molecular resonance. When living tissue is resonated within a given range of frequencies, typically 250 KHz to 16 MHz, the molecules within the tissue resonate and cause the tissue to be destroyed. The energy provided to cut the tissue is normally transmitted in the form of a controlled sinusoidal wave which causes relatively constant destruction to the tissue.
When tissue is to be coagulated, it is preferable that the tissue be resonated to a point where tissue destruction is initiated, but that the tissue destruction be controlled or limited. Most prior art systems generate a damped sinusoidal wave which causes tissue destruction to commence, but allows the tissue to anneal resulting in tissue coagulation.
Many prior art coagulators use periodic damped sinusoidal waves to coagulate the tissue. However, there is a strong tendency for a second resonant frequency to develop as the damped sinusoidal waves overlap. This produces an uncontrolled sinusoidal signal which could ultimately destroy the tissue.
There is a need for an RF generator which transmits bursts of frequencies aperiodically to form damped sinusoidal waves. It would also be beneficial to be able to shift the time domain over which the frequency bursts occur to prevent the repetition of frequency patterns from occurring in future frequency bursts.